The present invention relates to a convergence system to be used for a cathode-ray tube which has a plurality of electron beams, especially it relates to a convergence system to be used for a cathode-ray tube which has a plurality of in-line electron beams.
In a conventional convergence system, for example, as described in a Japanese patent application publication No. 50-27966 and the corresponding U.S. Pat. No. 3,430,099, a device for compensating horizontal misconvergence of electron beams and a device for compensating vertical misconvergence of electron beams are constituted separately, and each of them is provided with pole pieces and convergence yokes respectively.
In such a conventional example, it is possible to make convergence adjustment between the beams on both ides of a center beam with the above-mentioned convergence yokes, but it is impossible to make convergence adjustment (comatic aberration correction) between a side beam and the center beam.
In a general color cathode-ray tube, the center beam is a G (green) beam and the beams on both sides are a R (red) beam and a B (blue) beam.